9. Patients with <10 indexed Wood units, greater than moderate mitral regurgitation, mean pulmonary venous pressure > 16 mm Hg, pulmonary venous "v" waves > 20 mm Hg, systemic ventricular end-diastolic pressure > 16 mm Hg; patients with recognized extracardiac systemic venous collaterals to the pulmonary venous circulation, patients with recognized hepatic wedge pressure-inferior vena cava pressure gradient > 12 mm Hg.